On Tue, May 18, 2021 at 03:40:18PM +0100, Ferruh Yigit wrote: > On 5/14/2021 10:53 AM, Chengwen Feng wrote: > > Currently, the SVE code is compiled only when -march supports SVE > > (e.g. '-march=armv8.2a+sve'), there maybe some problem[1] with this > > approach. > > > > The solution: > > a. If the minimum instruction set support SVE then compiles it. > > b. Else if the compiler support SVE then compiles it. > > c. Otherwise don't compile it. > > > > [1] https://mails.dpdk.org/archives/dev/2021-April/208189.html > > > > Hi Chengwen, > > As far as I understand from above problem statement, you want to produce a > binary that can run in two different platforms, one supports only NEON > instructions, other supports NEON + SVE. > > For this driver should be compiled in a way to support min instruction set, > which is NEON. > > There are two build items, > > 1) hns3_rxtx_vec_sve.c > 2) rest of the library > > There is already runtime checks to select Rx/Tx functions, so it is safe to > build (1) as long as compiler supports. If the platform doesn't support SVE, > the > SVE path won't be selected during runtime. > > For (2), it should be build to support NEON only, if it is compiled to support > SVE, it won't run on the platform that only supports NEON. > > So, in below, if '__ARM_FEATURE_SVE' is supported, all driver is build with > SVE > support, won't this cause a problem on the NEON platform? > In that case, the rest of DPDK is being build with SVE so having one driver neon-only doesn't really make sense.
Overall, the patch looks to mirror what we do for AVX2/AVX512 support in the Intel drivers, so looks ok to me. /Bruce
